The present invention relates generally to a torque-transmitting system, and in particular to such a system which is usable with special advantage (but not exclusively) in a hammer drill or the like.
It is known in the art to provide drill bits which are formed at a rear end of their shaft with splines whose edges extend parallel to the longitudinal axis of the drill bit. Such drills are used as a rule in manually held power drilling machines of relatively heavy size, that is machines weighing on the order of 20 or more pounds. It has been found that if this type of drill is used in smaller and therefore lighter power drilling machines, the lighter weight of the machines does not press the drill bit with sufficient force against the workpiece, so that at least under disadvantageous circumstances it may happen that the drill bit becomes momentarily separated from its axial abutment in the tool holder of the machine as the machine is operated. This is particularly true in hammer drills wherein the drill bit is not only rotated but also has axially acting impacts imparted to it. When a momentary separation between the rear end of the drill bit and its axial abutment in the tool holder of the housing of the machine occurs, the result is a loss in impact energy which is therefore not transmitted to the drill bit, and an increase wear of the splines will occur.